Suspension system for a camera and light stage



Feb. 13, 1940. J, BQSSART y 2,190,093

S'USIPENSION SYSTEM FOR A CAMERA AND LIGHT STAGE A 4 Sheets-Sheet 1 Filed June 23, 1939 P61113, 1940. J, BQSSART 2,190,093

SUSPENSION SYSTEM FOR A CAMERA AND LIGHT STAGE Filed June 23, 1939 4 Sheets-Sheet 2 Feb. 13, 1940. J. `BossART SUSPENSION SYSTEM FOR A CAMERA AND- LIGHT STAGE Filed June 23, 1939 Y4, Sheets-Sheet 3 J. BOSSART A Feb. 13, 1940.

SUSPENSION SYSTEM FOR A CAMERA AND LIGHT STAGE 4 Sheets-Sheet 4 Filed June 23, 1939 Patented Feb. 13, 1940 UNITED STATES PATENT ortica John Bossart, Los Angeles, Calif., assignor to Loews Incorporated,

Ware

a corporation of Dela- Appiicaxion June 23, 1939, serial No. 280,762

7 Claims.

`My invention relates to a suspension system for a mobile stage for use in carrying cameras and lights during filming of motion pictures. The

type of stages now in use are of the xed type.

a They are built in place with scaffolding, or are carried on Aoverhead runners to a certain position and there fixed stationary by means of guy Wires or scaffolding timbers. My invention does away with the use of all scaffolding or rigidly fastened guy Wires.

In photographing motion pictures, the lights and cameras are often used in an overhead position. They must be held in a rigid position so that there is no motion imparted to them and the stage carrying them must notv sway. The lights used are usually arc lights whichA have to be periodically adjusted by a light man. His motions on the stage from one light to the other are quick and the stage carrying these lights must not move when the light man runs across it.

It is therefore, an object of my invention to provide a suspension system for a stage, carrying lights or cameras, which will prevent motion of the stage.

Another object of my invention is to provide a suspension system for a light or camera stage that will permit the stage to be readily raised or lowered or moved horizontally.

Other objects and advantages will be apparent from a study of the following specification.

In describing the invention, reference will be had to the appended drawings, in which Fig. l is a side View of the suspension system f or the mobile stage.

Fig. 2 is a rear view of the stage in an elevated position. 1

Fig. 3 is a front view of the movable carrier.

Fig. 4 is a plan view of the carrier from which the stage is suspended.

Fig. 5 is a detail view of the means for attaching the suspension cables.

Fig. 6 is a sectional View taken on the line 6-8 of Fig. 5.

Fig. 7 is a sectional view of the hydraulic ram by which the rear suspension cables are attached to the stage.

The stage I, suspended in accordance with my invention, is shown in Fig. 1 in three positions. This stage I may be an ordinary wooden 5. frame with board planking. The stage is supported by four pairs of paired cables 2-2a, 33a, 5-5a and 6--6a, and a pair of rear cables 4a. Cables 2-2a and 3-3a are attached to the rightv side of the stage S ,adjacent to the M. corners and cables ll--a are attached to the,

rear of the stagenearthe center; cables 5-5a and G-Ea are attached to the left side adjacent to the corners. Cables i2-2a are attached adjacent to one of the corners of the stage by means ot the bridle l composed of ashort piece of cable having eyes and En formed by looping the ends thereof and applying' cable clamps IU. Cable 2 has a similar eye which engages with eye and cable E--a is similarly attached to eye t. The bridle 'I passes through the cable stops Il and around the pulley I2 which is nonrotatably mounted by welding or bolting to plate I3. The plate I3 is bolted adjacent to the corners of stage I. In a like manner cables 3--3a 5-5a and 6-5a are attached adjacent to the other three corners of the stage I.

The other end of the cable it passes through the rotatable pulleys I4 and I5 mounted on the carrier lli to the drum l1, Where it is fastened by any suitable means. The cable Z-a similarly passes through the rotatable pulleys I8 and Hl to the drum 2li, where it is attached. The cable 3 passes through the rotatable pulleys 2! and 22 to the drum ll, where it is attached. The cable 3-cL passes through the rotatable pulleys 23 and 24 to the drum Eil, Where it is attached. The cables 5--5c, l-Ga similarly run through the corresponding pulleys 25, 25, 21, 28, 2t, 30, 3i and 32, and are attached to the drums i'l and 20 in the opposite directions to cables 2-2a and 3-3a, so that rotation of the drums Il and 26 will cause all the cables to be either reeled in or out simultaneously.

The drums Il' and 2G are driven in the same direction and at the same speed by the reversible motor 33 by means of a gear system enclosed in a housing 34. The drums Il and 2l] have the same diameters so as to wind all-the cables in or out the same amount atv the same speed.

The drums ll and must have separate sections for all the cables to be wound on so that there will be no overlapping. Cables 44a are attached to the rear of the stage I by means of a hydraulic ram 35, to be hereinafter de- Iscribed. The other end of the cables 4-4a run to the drum 2B by Way of pulleys 3&5 and 3l and are fastened to the drum 2t so that they are both wound in or out at the same speed and in the same direction as the cables l-f-Za, etc.

The diameters of the puileys it. i3, 2l to 23, 25, 2l, and 3l must be the same and the distance between pulleys I4 and I8 and pulleys 2i and 23, and similarly `pulleys 25 and 21, and 29 and 3|', must be the saine. By so spacing the pulleys the angle between cables 2-2a is the each cable will be taut.

same angle as between any other pair of cables, such as 3-3a or E-Ea. The pulleys 36 and 31 must be so spaced as to cause the angle be` tween the cables 4-4a to be the same as 2-2a. It then becomes apparent that the-rotation of the drums I'I and 20 will cause all ten cables to be wound in or out the same amount and The drums I'I and 20 must be matched in diameter.

It is readily apparent that all of the supportand 25 are not in a vertical plane with the front of the stage I, a lateral bracing will be achieved bythese cables which cooperate with the lateral bracing of the rear cables 4-4a. However this angle from a vertical plane and the sides of stage I must be lthe same on both sides and the rear cables must have the same angle; otherwise they will not holst and lower simultaneously. An increase in this angle will give greater stability.

Because of the lessening of the angle between the cables as the stage is lowered, there is more tendency for it to sway. When the stage is raised to its highest position, the angles become so great that swaying is totally eliminated. To prevent disarrangernent `of the cables, I prefer never to lower the stage into Contact with the oor 38, but always to maintain it at least two feet thereabove.

The carrier I6 is attached tothe overhead track 39 by rollers commonly used in the art. The track may be a special track attached to the cross beams 49, as shown in Fig. 2, or a simple beam 4l as shown in Fig. v1. Methods of supporting the carrier IS from an overhead track are well known in the art, and any of the diierent means may be used. Of course if the stage I is to be used for cameras, the overhead track and rollers will have to be of the type having a very smooth rolling surface and little friction. A carrier sus-` pended in this way permits the stage to be moved horizontally. f It is apparent that the cables supporting the stage I will not have a micrometer even thickness, even though this is desirable, Therefore to prevent a cable 2 with a larger thickness from caus ing its corresponding cable Z--a to become slack, I have made the pulley I 2 rigid and nonrotating. If the cable 2 becomes tighter than the cable 2-a the bridle 'I will slip in the groove 42 of the pulley I2 and equalize the load on thecables. If these cables were made rotatable, the action of a person walking across the stage l would cause the pulley to rotate and change the tension on the cable, and thus cause a swaying of the stage.

To prevent accident if one cable breaks, I have provided the pulley guard II which is welded in the form of a loop to the pulley I2 and the plate I3. If the cable breaks, the bridle 'I will slip through the pulley until the cable clamp It engages the pulley guard II and will then stop. Thus in this way the corner with the broken cable will still be supported by one of the pairedcables.

Any slight variance in the length of one pair of cables, such as 2-2a, and the length of another of the paired cables, such as testo, caused by not cause more than a fraction of an inch rise or g fall of a corner of the stage and the twisting of the wooden platform issufiicient to take care of this difference in length. f

To prevent a change in the tension vof cables 4-4a and thus produce sway in the stage I, these cables are attached to the stage by means oi hydraulic rams 35 which will prevent the sudden motion of an operator on the stage from moving them. 4 The hydraulic rams 35 are composed of a cylinder 43 having one end sealed and a flange 44 thereon for bolting to the rear of the stage. On the upper end of the cylinder 43 is a suitable closure member 45 having a passage through its center for a piston rod 46.

The piston rod 46 has on its outer end a lug 41 l'or attaching the cable 4 and at its other end a piston 48. The piston 48 is immersed in oil or water 49 contained in the cylinder 43. A da phragm 5I! is placed in the cylinder intermediate the piston 4t and the top entrance 5I of a return pipe 52. The lower entrance to the pipe 52' is below the piston.

Any

A heavy spring 54 is placed around the piston v rod 46 with its lower end engaging a collar 55 on the piston rod 46 and its upper end engaging the closure member 45. If a sudden tension is placed on the cable, it will be transmitted by way of the lug 4'I to the piston rod 4B and the piston 48 which will very slowly move upward in the cylinder 43 because of leakage between the piston rod 48 and the cylinder 43. The motion ofthe piston 48 will therefore be very slow and prevent anyv sudden lengthening of the cable 4 and motion` of the stage I. Likewise if the motion is in the other direction, the spring 54 will likewise force the piston 48 downward and the leakage will permit slow motion.`

While I have shown and described the preferred embodiments of my invention, I do not wish to be limited to any details herein described, except as defined in the appended claims.

I claim:

l. In a supporting system 'for a movable stage, the combination of a carriage and a rectangular l stage, said stage having four sets of paired cables attached to two opposite sides of said stage adjacent the corner, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables make an angle between cables and the angle between any two cables of a pair isequal to the angle between the cables of any other pair, a pair of cables adjacent either of the remaining sides of the stage, and extending angles between the two cables of any other pair..

2. In a supporting system for a movable stage, the combination of a carriage and a rectangular stage, said stage having four sets of paired cables attached to two opposite sides of said stage adjacent the corner, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables make an angle between cables and the angle between any two cables of a pair is equal to the angle between the cables of any other pair, a pair of cables adjacent either4 ci the remaining sides of the stage and supported from the carriage so that the angles between them are equal to the angles between the two cables ol' any other pair, and a bridle for said paired cables and a nonrotatable pulley around which said bridle passes.

3. In a supporting system for a movable stage, the combination of a carriage and a. rectangular stage, said stage having four sets of paired cables attached 'to two opposite sides of said stage adjacent the corner, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables make an angle between cables and the angle between any two cables of a pair is equal to the angle between the cables of any other pair, a pair of cables adjacent either of the remaining sides of the stage and supported from the carriage so that the angles between them are equal to the angles between the two cables of any other pair, a bridle for said paired cables, a nonrotatable pulley around which said bridle passes, and cable stop means.

4. In a supporting system for a movable stage,

the combination of a carriage and a rectangular stage, said stage having four sets of paired cables attached to two opposite sides of said stage adjacent the corner, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables make an angle between cables and the angle between any two cables of a pair is equal to the angle between the cables of any other pair, a pair of cables adjacent either of the remaining sides of the stage and supported from the carriage so that the angles between them are equal to the angles between the two cables of any other pair, a bridle for said paired cables, a nonrotatable pulley around which said bridle passes, and a hydraulic ram between the last described cables and the stage.

5. In a supporting system for a movable stage, the combination of a carriage and a rectangular stage, said stage having four sets of paired cables attached to two opposite sides of said stage adjacent the corners, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables make an angle between cables and the angle between any two cables of a pair is equal to the angle between the cables of any other pair, a pair of cables adjacent either of the remaining sides of the stage and supported from the carriage so that the angles between them are equal to the angles between the two cables of any other pair, and a hydraulic ram between the last described cables and the stage.

6. In a supporting system for a movable stage, the combination of a carriage and a rectangular stage, said stage having paired cables attached to the two sides of said stage adjacent the corners, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables have an angle between said cables and the angle between any two cables of a pair is equal to the angle between the cables of any other pair, a pair of cables attached to either of the remaining sides of the stage extending in a plane at right angles to the plane of the other pair of cables and supported from the carriage so that the angles between them are equal to the angles between the two cables of any of said paired cables, said paired cables at an angle from a vertical plane and the plane of the sides of the stage they are attached to and all of the other cables lying in a plane, making a corresponding angle.

'7. In a supporting system for a movable stage, the combination of a carriage and a rectangular stage, said stage having paired cables attached to the two sides of said stage adjacent the corners, the paired cables supported from said carriage at equal distances so that the two cables of said paired cables have an angle between said cables and the angle between any two cables of a pair is equal to the angle between the cables of any other pair, a pair of cables attached to either of the remaining sides of the stage and supported from the carriage so that the angles between them are equal to the angles between the two cables of any of said paired cables, said paired cables at an angle from a vertical plane and the plane of the sides of the stage they are attached to and all of the other cables lying in a plane, making a corresponding angle, and nonrotatable pulleys to which said paired cables are attached.

JOHN BOSSART. 

